Dell EMC PowerStore · 2020-05-18 · Multipathing Software Configuration ... Inconsistent LUNs may...

Dell EMC PowerStoreHost Configuration Guide

1.0

May 2020Rev. A00

Notes, cautions, and warnings

NOTE: A NOTE indicates important information that helps you make better use of your product.

CAUTION: A CAUTION indicates either potential damage to hardware or loss of data and tells you how to avoid the

problem.

WARNING: A WARNING indicates a potential for property damage, personal injury, or death.

© 2020 Dell Inc. or its subsidiaries. All rights reserved. Dell, EMC, and other trademarks are trademarks of Dell Inc. or itssubsidiaries. Other trademarks may be trademarks of their respective owners.

Additional Resources...................................................................................................................... 5

1 Best Practices for Storage Connectivity......................................................................................... 6General SAN Guidelines........................................................................................................................................................ 6

Recommended Zoning Configurations..........................................................................................................................6Using LUN 0 with PowerStore.......................................................................................................................................6

Fibre Channel SAN Guidelines..............................................................................................................................................6Recommended Configuration Values Summary.......................................................................................................... 6Minimal Zoning Configuration for Fibre Channel..........................................................................................................7Recommended Zoning Configuration for Fibre Channel.............................................................................................7

iSCSI SAN Guidelines............................................................................................................................................................ 8Recommended Configuration Values Summary.......................................................................................................... 8Minimal Subnetting Configuration for iSCSI.................................................................................................................9Recommended Configuration for iSCSI........................................................................................................................9

2 Host Configuration for VMware vSphere ESXi................................................................................11Chapter Scope...................................................................................................................................................................... 11Recommended Configuration Values Summary................................................................................................................11Fibre Channel HBA Configuration...................................................................................................................................... 12

Pre-Requisites.................................................................................................................................................................12iSCSI Configuration..............................................................................................................................................................12

Pre-Requisites.................................................................................................................................................................12Jumbo Frames................................................................................................................................................................ 13Delayed ACK................................................................................................................................................................... 13Login Timeout................................................................................................................................................................. 13

vStorage API for Array Integration (VAAI) Settings........................................................................................................13Confirming that VAAI is Enabled on the ESXi Host................................................................................................... 14

Setting the Maximum I/O................................................................................................................................................... 14Confirming UNMAP Priority................................................................................................................................................14Multipathing Software Configuration................................................................................................................................ 14

Configuring Native Multipathing...................................................................................................................................14Post-Configuration Steps................................................................................................................................................... 16

Disk Formatting.............................................................................................................................................................. 16Presenting PowerStore Volumes to the ESXi Host...................................................................................................16Creating a File System................................................................................................................................................... 16VMware Paravirtual SCSI Controllers..........................................................................................................................17Virtual Disk Provisioning.................................................................................................................................................17Virtual Machine Guest OS Settings............................................................................................................................. 17

3 Host Configuration for Microsoft Windows................................................................................... 18Recommended Configuration Values Summary...............................................................................................................18Fibre Channel HBA Configuration...................................................................................................................................... 18

Pre-Requisites.................................................................................................................................................................19iSCSI Configuration..............................................................................................................................................................19

Contents

Contents 3

Pre-Requisites.................................................................................................................................................................19Multipathing Software Configuration................................................................................................................................ 19

Configuring Native Multipathing Using Microsoft Multipath I/O (MPIO).............................................................. 19Post-Configuration Steps - Using the PowerStore Storage......................................................................................... 20

Disk Formatting..............................................................................................................................................................20Presenting PowerStore Volumes to the Windows Host.......................................................................................... 20Creating a File System...................................................................................................................................................21

4 Host Configuration for Linux....................................................................................................... 22Recommended Configuration Values Summary.............................................................................................................. 22Fibre Channel Configuration.............................................................................................................................................. 23

Pre-Requisites................................................................................................................................................................23iSCSI Configuration............................................................................................................................................................. 23

Pre-Requisites................................................................................................................................................................23Configuring the PowerStore Cluster Disk Device with iSCSI.................................................................................. 23Configuring the PowerStore Cluster Disk Device with iSCSI - Single Network Subnet Support.......................24

Multipathing Software Configuration............................................................................................................................... 25Configuring Linux Native Multipathing....................................................................................................................... 25

Post-Configuration Steps - Using the PowerStore Cluster.......................................................................................... 26Presenting PowerStore Cluster Volumes to the Linux Host....................................................................................27Partition Alignment in Linux..........................................................................................................................................27Creating a File System.................................................................................................................................................. 27

4 Contents

Additional ResourcesAs part of an improvement effort, revisions of the software and hardware are periodically released. Some functions that are described inthis document are not supported by all versions of the software or hardware currently in use. The product release notes provide the mostup-to-date information about product features. Contact your technical support professional if a product does not function properly ordoes not function as described in this document.

Where to get helpSupport, product, and licensing information can be obtained as follows:

• Product information

For product and feature documentation or release notes, go to the PowerStore Documentation page at www.dell.com/powerstoredocs.

• Troubleshooting

For information about products, software updates, licensing, and service, go to www.dell.com/support and locate the appropriateproduct support page.

• Technical support

For technical support and service requests, go to www.dell.com/support and locate the Service Requests page. To open a servicerequest, you must have a valid support agreement. Contact your Sales Representative for details about obtaining a valid supportagreement or to answer any questions about your account.

Preface

Additional Resources 5

https://www.dell.com/powerstoredocs

https://www.dell.com/powerstoredocs

https://dell.com/support

https://dell.com/support

Best Practices for Storage ConnectivityThis chapter contains the following topics:

Topics:

• General SAN Guidelines• Fibre Channel SAN Guidelines• iSCSI SAN Guidelines

General SAN GuidelinesThis section provides general guidelines for storage connectivity.

NOTE: This document describes mainly the storage-specific recommendations for PowerStore. It is recommended to

always consult with the OS documentation for the up-to-date guidelines specific for the used operating system.

NOTE: In hosts running a hypervisor, such as VMware ESXi, Microsoft Hyper-V or any clustering software, it is

important to ensure that the logical unit numbers of PowerStore volumes are consistent across all hosts in the

hypervisor cluster. Inconsistent LUNs may affect operations such as VM online migration or VM power-up.

Recommended Zoning ConfigurationsFollow these guidelines for zoning configuration:

• The optimal number of paths depends on the operating system and server information. To avoid multipathing performancedegradation, do not use more than 8 paths per device per host. It is recommended to use 4 paths.

• Keep a consistent link speed and duplex across all paths to the PowerStore cluster per single host or a cluster of hosts.• With a multi-appliance cluster, it is highly advised to zone the host to as many appliances as possible, in order to achieve best load

distribution across the cluster. Make sure to keep the minimum/optimal zoning recommendations for each appliance.NOTE: A multi-appliance cluster is not designed to provide better resiliency, but to provide better load balance. In

order to perform volume migration between appliances, a host must be zoned to both appliances.

Using LUN 0 with PowerStoreWhen a LUN ID#0 is not configured, and/or when the PowerStore volume is not assigned to an initiator and target pair, the PowerStorecluster exposes by default a SACD (Storage Array Controller Device) device as LUN ID#0.

Fibre Channel SAN GuidelinesThis section describes the best practices for attaching hosts to a PowerStore cluster in a highly available resilient and optimal FibreChannel SAN.

Recommended Configuration Values SummaryThe following table summarizes the recommended configuration values related to Fibre Channel SAN.

Validation Impact Severity Refer to Section

Use two separate fabrics. Redundancy Mandatory Recommended ZoningConfiguration for Fibre Channel

1

6 Best Practices for Storage Connectivity


Each host should be zoned to both nodes of eachappliance.

Redundancy Mandatory Minimal Zoning Configurationfor Fibre Channel

Maximum number of paths per appliance per volumeper host: 8

Performance Warning Recommended ZoningConfiguration

Recommended number of paths per volume per host:4


Link speed should be consistent across all paths tothe PowerStore cluster per single host or a cluster ofhosts.


Balance the hosts between the nodes of theappliance to provide a distributed load across alltarget ports.

Performance Recommended Recommended ZoningConfiguration

Maximum ISL Hops: 2 Performance Recommended Recommended ZoningConfiguration for Fibre Channel

Minimal Zoning Configuration for Fibre ChannelTo prevent a host path failure due to a single node failure, follow these guidelines:

• A PowerStore appliance contains two nodes.• A host must be zoned at minimum with one path to each node for redundancy.

NOTE: The diagrams throughout this chapter illustrate possible implementations of these guidelines. Other possible

implementations are not illustrated.

1. Host2. PowerStore Appliance3. Fibre Channel Switch4. Node

Recommended Zoning Configuration for Fibre ChannelWhen setting up a Fibre Channel SAN infrastructure, follow these guidelines:

• Use two separate fabrics. Each fabric should be on a different physical FC switch for resiliency.• Balance the hosts between the two nodes of the appliance.

Best Practices for Storage Connectivity 7

• The PowerStore cluster can be shipped with various extension modules for Fibre Channel. If your PowerStore cluster contains morethan one extension I/O module per node, distribute the zoning among all I/O modules for highest availability and performance.

• Use single initiator zoning scheme: Utilize single-initiator per multiple-target (1:many) zoning scheme when configuring zoning with aPowerStore cluster.

• Host I/O latency can be severely affected by FC SAN congestion. Minimize the use of ISLs by placing the host and storage ports onthe same physical switch. When this is not possible, ensure that there is sufficient ISL bandwidth and that both the Host andPowerStore cluster interfaces are separated by no more than 2 ISL hops.

• For more information on zoning best practices, refer to the Networked Storage Concepts and Protocols techbook: https://support.emc.com/docu33913_Networked-Storage-Concepts-and-Protocols-TechBook.pdf

• PowerStore supports direct attachment of hosts to the appliances.

The following diagram describes a simple connectivity.

1. Host2. PowerStore Appliance3. FC SAN Switch4. Node

NOTE: Refer to your Fibre Channel switch user manual for implementation instructions.

iSCSI SAN GuidelinesThis section details the best practices for attaching hosts to a PowerStore cluster in a highly-available, resilient and optimal iSCSI SAN.

Recommended Configuration Values SummaryThe following table summarizes the recommended variables related to iSCSI SAN:


Each host should be connected to bothnodes of each appliance.

Redundancy Mandatory Minimal Subnetting Configurationfor iSCSI

Maximum number of paths per volume perhost: 8


Recommended number of paths per volumeper host: 4


Link speed should be consistent across allpaths to the PowerStore cluster.



https://support.emc.com/docu33913_Networked-Storage-Concepts-and-Protocols-TechBook.pdf

https://support.emc.com/docu33913_Networked-Storage-Concepts-and-Protocols-TechBook.pdf


Duplex setting should be consistent across allpaths to the PowerStore cluster per singlehost or a cluster of hosts.


If jumbo frames are required for iSCSI traffic,all ports (server, switches and storage) mustbe configured with the same MTU value.

Performance Warning Recommended Configuration foriSCSI

Flow control must be disabled on all ports(server, switches and storage).


Enable the TCP Offloading Engine (TOE) onthe host iSCSI interfaces.


Balance the hosts across the target ports ofthe appliances to provide a distributed loadacross all target ports.

Performance Recommended Recommended ZoningConfiguration

Use dedicated NICs or iSCSI HBAs forPowerStore cluster iSCSI connection.

NOTE: Avoid partitioning the iSCSIinterface.

Performance Recommended Recommended Configuration foriSCSI

In PowerStore only single network subnet issupported for the iSCSI target portals.

Performance Normal Recommended Configuration foriSCSI

Minimal Subnetting Configuration for iSCSITo prevent host path failure due to a single node failure, follow these guidelines:

• A PowerStore Appliance contains two nodes.• A host must be connected at minimum with one path to each node for redundancy.

Recommended Configuration for iSCSIWhen setting up an iSCSI SAN infrastructure, follow these guidelines:

• iSCSI switch recommendations

○ Use nonblocking switches○ Use enterprise grade switch○ Utilize at minimum 10GbE interfaces

• Use dedicated iSCSI switches. If not possible, use dedicated iSCSI VLANs on the switches.• Disable flow control features on the servers, switches and system ports.• It is recommended to use dedicated NICs or iSCSI HBAs for PowerStore cluster iSCSI and not to partition the iSCSI interface (that is,

disable NIC Partitioning - NPAR).• Enable the TCP Offloading Engine (TOE) on the host iSCSI interfaces, to offload the TCP packet encapsulation from the host's CPU

to the NIC or iSCSI HBA, and free up CPU cycles.• When using PowerStore iSCSI, it is recommended to use interfaces individually rather than using NIC Teaming (Link Aggregation), to

combine multiple interfaces into a single virtual interface.• In PowerStore only single network subnet is supported for the iSCSI target portals and routing is not supported.• If Jumbo Frames are required for iSCSI traffic, make sure that all ports (servers, switches and system) are configured with the same

MTU value.

NOTE: VMware requires setting Jumbo Frames at the virtual switch and VMKERNEL level.

NOTE: Refer to your iSCSI switch user manual for instructions on the implementations.

The following diagram describes simple connectivity.

Best Practices for Storage Connectivity 9

1. Host2. PowerStore Appliance3. iSCSI Switch4. Node

NOTE: Make sure to connect port 0 of each node to a different iSCSI switch.

NOTE: Refer to your iSCSI switch user manual for implementation instructions.


Host Configuration for VMware vSphere ESXi

This chapter contains the following topics:

Topics:

• Chapter Scope• Recommended Configuration Values Summary• Fibre Channel HBA Configuration• iSCSI Configuration• vStorage API for Array Integration (VAAI) Settings• Setting the Maximum I/O• Confirming UNMAP Priority• Multipathing Software Configuration• Post-Configuration Steps

Chapter ScopeThis chapter provides guidelines only for configuring ESXi hosts that are connected externally to PowerStore. For configuring an internalESXi host in PowerStore, refer to the PowerStore Virtualization Guide document.

Recommended Configuration Values SummaryThe following table summarizes all used and recommended variables and their values when configuring hosts for VMware vSphere.

NOTE: Unless indicated otherwise, use the default parameters values.


Validation: Specify ESXi as the operatingsystem for each defined host.

Serviceability Mandatory Presenting PowerStoreVolumes to the ESXi Host

ESXi configuration: VAAI should beenabled, therefore:

• DataMover.HardwareAcceleratedMove =1

• DataMover.HardwareAcceleratedInit =1

• VMFS3.HardwareAcceleratedLocking=1

Performance Mandatory Confirming that VAAI isEnabled on the ESXi Host

ESXi configuration:Disk.DiskMaxIOSize = 1024

Stability & Performance Mandatory Setting Maximum I/O

ESXi configuration: Keep the UNMAPpriority for the host at the lowestpossible value (default value for ESXi6.5).

Stability & Performance Mandatory Confirming UNMAP Priority

Path selection policy: VMW_PSP_RR Stability & Performance Mandatory Configuring vSphere NativeMultipathing

Alignment: Guest OS virtual machinesshould be aligned.

Storage efficiency &Performance

Warning Disk Formatting

2

Host Configuration for VMware vSphere ESXi 11


iSCSI configuration: Configure end-to-end Jumbo Frames.

Performance Recommended Jumbo Frames

iSCSI configuration: Disable DelayedACK on ESXi.

Stability Recommended Delayed ACK

iSCSI configuration: AdjustLoginTimeOut to 30.

Stability Recommended Login Timeout

Path switching: Switch for every I/O. Performance Recommended Configuring vSphere NativeMultipathing

Virtual Disk Provisioning: Use thinprovisioned virtual disks.

Performance Recommended Virtual Machine Formatting

Virtual machine configuration: Configurevirtual machines with ParavirtualizedSCSI controllers.

Stability & Performance Recommended VMware Paravirtual SCSIcontrollers

RDM volumes: In Guest OS, span RDMvolumes used by the virtual machineacross SCSI controllers.

Performance Recommended Virtual Machine Guest OSSettings

NOTE: For information on virtualization and Virtual Volumes, refer to the PowerStore Virtualization Guide and the BestPractices Guide.

Fibre Channel HBA ConfigurationThis section describes the recommended configuration that should be applied when attaching hosts to PowerStore cluster using FibreChannel .

NOTE: This section applies only to Fibre Channel. If you are using only iSCSI, go to iSCSI HBA Configuration.

NOTE: Review Fibre Channel SAN Guidelines before you proceed.

Pre-RequisitesBefore installing HBAs on an ESXi host, the following pre-requisites should be met:

• Refer to the E-Lab Interoperability Navigator (https://elabnavigator.emc.com) for supported FC HBA models and drivers.• Verify that all HBAs have supported driver, firmware and BIOS versions.• Verify that all HBAs BIOS settings are configured according to E-Lab recommendations.

iSCSI ConfigurationThis section describes the recommended configuration that should be applied when attaching hosts to a PowerStore cluster using iSCSI.

NOTE: This section applies only for iSCSI. If you are using only Fibre Channel with vSphere and PowerStore, go to Fibre

Channel HBA Configuration.

NOTE: Be sure to review iSCSI SAN Guidelines before you proceed.

Pre-RequisitesBefore configuring iSCSI, the following pre-requisites should be met:

• Follow the VMware recommendations for installation and setup of the appropriate NIC/iSCSI HBA for your system.• It is recommended to install the latest driver version (patch), as described in the VMware support site for each specific NIC/iSCSI

HBA.

12 Host Configuration for VMware vSphere ESXi

https://elabnavigator.emc.com

• Refer to the E-Lab interoperability Navigator (https://elabnavigator.emc.com) for supported NIC/iSCSI HBA models and drivers.

Jumbo FramesFollow these guidelines for configuring Jumbo Frames with ESXi hosts.

When using iSCSI with ESXi hosts and PowerStore, it is recommended to configure end-to-end Jumbo Frames (MTU=9000) for optimalperformance. With Jumbo Frames, Ethernet frames are set to be larger than 1500 bytes (up to 9000 bytes).

NOTE: When using Jumbo Frames, make sure that all ports (ESXi server, switch/es and storage) are configured with

the correct MTU value. With VMware ESXi, the correct MTU size must be set on the virtual switch as well.

For further details on configuring Jumbo Frames with iSCSI on ESXi, refer to VMware KB article 1007654 on the VMware website(https://kb.vmware.com/kb/1002598).

Delayed ACKFor optimal traffic, it is recommended to disable Delayed ACK on ESXi.

For optimal iSCSI traffic between the ESXi hosts and PowerStore, especially during periods of network congestion, it is recommended todisable Delayed ACK on ESXi. By disabling Delayed ACK, the ESXi host would send an ACK acknowledgment segment for every receiveddata segment (rather than delaying the sending of ACK acknowledgment segments, while receiving a stream of TCP data segments).

For further details on the Delayed ACK parameter and how to disable it using the vSphere Client, refer to VMware KB article 1002598 onthe VMware website (https://kb.vmware.com/kb/1002598).

NOTE: The recommended method for configuring the Delayed ACK setting is per discovered iSCSI target. This allows to

disable Delayed ACK only for PowerStore iSCSI targets.

Login TimeoutFollow these steps to set the iSCSI login timeout.

About this task

When establishing an iSCSI session between the initiator and target, the login timeout setting controls how long the ESXi host attempts tolog in to the iSCSI target before failing the login and retrying. The default setting for LoginTimeOut is 5. For example, by default aniSCSI session ceases retries after 20 seconds (5 times the LoginRetryMax setting, which is set by default to 4).

To optimize the iSCSI session behavior with PowerStore and to better handle periods of network disruptions, it is recommended to adjustLoginTimeOut to 30.

The following steps describe how to adjust LoginTimeOut, using command-line.

Steps

1. Connect to the ESXi host as root.

2. Run the following command:

esxcli iscsi adapter param set -A adapter_name -k LoginTimeout -v value_in_secExample

For example:

esxcli iscsi adapter param set -A vmhba64 -k LoginTimeout -v 30

vStorage API for Array Integration (VAAI) SettingsPowerStore Storage cluster fully supports VAAI. VAAI must be enabled on the ESXi host before using PowerStore.

VAAI is an API that offloads operations such as virtual machine provisioning, storage cloning, and space reclamation to storage clustersthat supports VAAI. PowerStore clusters fully support VAAI.

To ensure optimal performance of PowerStore storage from vSphere, VAAI must be enabled on the ESXi host before using PowerStorestorage from vSphere. Failing to do so may expose the PowerStore cluster to the risk of datastores becoming inaccessible to the host.

This section describes the necessary settings for configuring VAAI for PowerStore storage.



https://kb.vmware.com/kb/1002598

https://kb.vmware.com/kb/1002598

Confirming that VAAI is Enabled on the ESXi HostFollow these instructions to confirm that VAAI is enabled on the ESXi host.

About this task

When using vSphere ESXi version 6.5 and above, VAAI is enabled by default. Before using the PowerStore storage, confirm that VAAIfeatures are enabled on the ESXi host.

Verify that the following parameters are enabled (that is, set to 1):

• DataMover.HardwareAcceleratedMove• DataMover.HardwareAcceleratedInit• VMFS3.HardwareAcceleratedLockingIf any of the above parameters are not enabled, click the Edit icon and click OK to adjust them.

Setting the Maximum I/OFollow this guideline to set the maximum I/O request size for storage devices.

Disk.DiskMaxIOSize determines the maximum I/O request size passed to storage devices. With PowerStore, it is required to changethis parameter from 32767 (the default setting of 32MB) to 1024 (1MB).

NOTE: For details on a possible Windows EFI boot issue with PowerStore storage (in case the above maximum I/O block

size setting adjustment cannot be done), refer to VMware KB article 2137402 on the VMware website (https://

kb.vmware.com/s/article/2137402).

Confirming UNMAP PriorityThis topic provides steps for setting UNMAP priority on a DataStore.

Prerequisites

NOTE: Provisioning Virtual Disks with UNMAP set to a non-default priority on a DataStore provisioned on PowerStore

may result in an increased amount of write I/Os to the storage subsystem. It is therefore highly recommended to keep

UNMAP set to a default priority.

To set UNMAP priority on a datastore:

Steps

1. Access vSphere Client and locate the ESX Storage Configuartion panel.2. Go to the Storage tab.3. Right-click the affected DataStore.4. Click Edit Space Reclamation.5. Set the value (with ESX 6.7 or later, set to 100MB/s, with ESX 6.5, set to Low).6. Click OK.

Multipathing Software Configuration

Configuring Native MultipathingFollow these guidelines when configuring the vSphere ESXi host with native multipathing

PowerStore supports the Native Multipathing Plugin (NMP). This section describes the procedure required for configuring nativemultipathing for PowerStore volumes.

For best performance, it is recommended to do as follows:

• Set the NMP Round Robin path selection policy on PowerStore volumes presented to the ESXi host.


https://kb.vmware.com/s/article/2137402

https://kb.vmware.com/s/article/2137402

• Set the NMP Round Robin path switching frequency to PowerStore volumes from the default value (1000 I/O packets) to 1.

These settings ensure optimal distribution and availability of load between I/O paths to the PowerStore storage.

Configuring NMP Round Robin as the Default Pathing Policy for AllPowerStore VolumesFollow this procedure to configure NMP Round Robin as the default pathing policy for all PowerStore volumes using the ESXi commandline.

About this task

NOTE: As of VMware ESXi version 6.7, Patch Release ESXi670-201912001, the satp rule presented in this procedure is

already integrated into the ESXi kernel.

NOTE: Use this method when no PowerStore volume is presented to the host. PowerStore volumes already presented to

the host are not affected by this procedure (unless they are unmapped from the host).

Steps

1. Open an SSH session to the host as root.

2. Run the following command to configure the default pathing policy for newly defined PowerStore volumes to Round Robin with pathswitching after each I/O packet:

esxcli storage nmp satp rule add -c tpgs_on -e "PowerStore" -M PowerStore -P VMW_PSP_RR -Oiops=1 -s VMW_SATP_ALUA -t vendor -V DellEMCThis command also sets the NMP Round Robin path switching frequency for newly defined PowerStore volumes to switch every I/O.

Next steps

NOTE: Using this method does not impact any non-PowerStore volume presented to the ESXi host.

Configuring NMP Round Robin on a PowerStore Volume AlreadyPresented to the ESXi HostFollow this procedure to configure NMP Round Robin on a PowerStore volume that is already presented to the ESXi host, using ESXicommand line:

About this task

NOTE: Use this method only for PowerStore volumes already presented to the host. For volumes not yet presented to

the host, refer to Configuring vSphere NMP Round Robin as the default pathing policy for all volumes.

Steps

1. Open an SSH session to the host as root.

2. Run the following command to obtain the NAA of PowerStore LUNs presented to the ESXi host:

#esxcli storage nmp path list | grep PowerStore -B13. Run the following command to modify the path selection policy on the PowerStore volume to Round Robin:

#esxcli storage nmp device set --device="<naa_id>" --psp=VMW_PSP_RRFor example:

#esxcli storage nmp device set --device="naa.68ccf098003f1461569ea4750e9dac50" --psp=VMW_PSP_RR

4. Run the following command to set the NMP Round Robin path switching frequency on PowerStore volumes from the default value(1000 I/O packets) to 1:

#esxcli storage nmp psp roundrobin deviceconfig set --device="<naa_id>" --iops=1 --type=iopsFor example:


#esxcli storage nmp psp roundrobin deviceconfig set --device="naa.68ccf098003f1461569ea4750e9dac50" --iops=1 --type=iops

Next steps

NOTE: Using this method does not impact any non-PowerStore volumes presented to the ESXi host.

For details, refer to VMWare KB articles 1017760 and 2069356 on the VMware weblite (http://kb.vmware.com/kb/1017760 and http://kb.vmware.com/kb/2069356 respectively).

Post-Configuration StepsWhen host configuration is completed, you can use the PowerStore storage from the host. For details on creating, presenting andmanaging volumes, refer to the PowerStore User Guide that matches the version running on your PowerStore cluster.

The Dell EMC Virtual Storage Integrator (VSI) version 8.4 and later plug-in can be used in to provision from within Virtual Machine FileSystem (VMFS) datastores and Raw Device Mapping volumes on PowerStore. Furthermore, the Dell EMC VSI Storage Viewer version 8.4and later plug-in extends the vSphere Client to facilitate the discovery and identification of PowerStore storage devices allocated toVMware ESXi hosts and virtual machines.

For further information on using these two vSphere Client plug-ins, refer to the VSI Unified Storage Management Product Guide and theVSI Storage Viewer Product Guide.

Disk FormattingFollow these guidelines for formatting PowerStore volumes:

When creating volumes in PowerStore for a vSphere ESXi host, the following considerations should be made:

• Disk logical block size - The only logical block (LB) size supported by vSphere ESXi for presenting volumes is 512 bytes.NOTE: For details on formatting a newly created volume, refer to the PowerStore User Guide that matches the

version running on your PowerStore cluster.

• Disk alignment - Unaligned disk partitions may substantially impact I/O to the disk.

With vSphere ESXi, datastores and virtual disks are aligned by default as they are created. Therefore, no further action is required toalign these in ESXi.

With virtual machine disk partitions within the virtual disk, alignment is determined by the guest OS. For virtual machines that are notaligned, consider using tools such as UBERAlign to realign the disk partitions as required.

Presenting PowerStore Volumes to the ESXi HostFollow these guidelines for presenting PowerStore volumes to the ESXi host.

NOTE: Using data reduction and /or encryption software on the host side will affect the PowerStore cluster data

reduction.

NOTE: When using iSCSI software initiator with ESXi and PowerStore storage, it is recommended to use only lower case

characters in the IQN to correctly present the PowerStore volumes to ESXi. For more details, refer to VMware KB

article 2017582 on the VMware website (http://kb.vmware.com/selfservice/microsites/search.do?

language=en_US&cmd=displayKC&externalId=2017582).

When adding host groups and hosts to allow ESXi hosts to access PowerStore volumes, specify ESXi as the operating system for newly-created hosts.

Creating a File SystemIt is recommended to create the file system using its default block size.

NOTE: File system configuration and management is out of the scope of this document.

It is recommended to create the file system using its default block size (using a non-default block size may lead to unexpected behavior).Refer to your operating system and file system documentation.


http://kb.vmware.com/kb/1017760



http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2017582


VMware Paravirtual SCSI ControllersFollow these guidelines for configuring virtual machines with Paravirtual SCSI controllers.

For optimal resource utilization of virtual machines with PowerStore, it is recommended to configure virtual machines with paravirtualizedSCSI controllers. VMware paravirtual SCSI controllers are high performance storage controllers that can provide higher throughput andlower CPU usage. These controllers are best suited for high performance storage environments.

For further details on configuring virtual machines with paravirtualized SCSI controllers, refer to the vSphere Virtual MachineAdministration Guide in the VMware vSphere documentation.

Virtual Disk ProvisioningFollow these recommendations for provisioning virtual disks on the PowerStore cluster.

For optimal space utilization with vSphere ESXi 6.x and above, it is recommended to provision virtual disks on the PowerStore cluster,using Thin Provisioning.

In Thin Provisioning format, in-guest space reclamation is available, provided the following minimum requirements are fulfilled:

• ESXi 6.x• Thin virtual disks• VM hardware version 11• EnableBlockDelete set to 1• Guest OS support of UNMAP

NOTE: Refer to the corresponding guest OS chapter within this document for instructions on how to efficiently create a

file system.

Virtual Machine Guest OS SettingsThis section details the recommended settings and considerations for virtual machines guest OS.

• LUN Queue Depth - For optimal virtual machine operation, configure the virtual machine guest OS to use the default queue depth ofthe virtual SCSI controller. For details on adjusting the guest OS LUN queue depth, refer to VMware KB# 2053145 on the VMwarewebsite (http://kb.vmware.com/kb/2053145).

• RDM volumes in guest OS - Span RDM volumes, used by the virtual machine, across SCSI controllers to prevent a bottleneck on asingle SCSI controller.

• RDM volumes in guest OS used for Microsoft Cluster (MSCS) - ESXi hosts with visibility to RDM volumes, used by Microsoft Cluster(MSCS) may take a long time to start or to perform LUN rescan.

For the required settings on the RDM volumes, refer to VMware KB# 1016106 (http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1016106).





Host Configuration for Microsoft Windows


Topics:

• Recommended Configuration Values Summary• Fibre Channel HBA Configuration• iSCSI Configuration• Multipathing Software Configuration• Post-Configuration Steps - Using the PowerStore Storage

Recommended Configuration Values SummaryThe following table summarizes all used variables and their values when configuring hosts for Microsoft Windows.



Validation: Specify Windows asthe operating system for eachdefined host.

Serviceability Mandatory Presenting PowerStore Volumes to the WindowsHost

Load balancing: Use Round Robinfor Microsoft Native MicrosoftMultipath I/O (MPIO) withWindows Server 2008 and above.

Performance Warning Configuring Native Multipathing using MicrosoftMultipath I/O (MPIO)

Temporarily disable UNMAPduring file systems creation:

• To temporarily disableUNMAP on the host (prior tofile system creation):

fsutil behavior setDisableDeleteNotify 1

• To re-enable UNMAP on thehost (after file systemcreation):

fsutil behavior setDisableDeleteNotify 0

Performance Recommended Creating a File System

Fibre Channel HBA ConfigurationThis section describes the recommended configuration that should be applied when attaching hosts to PowerStore cluster using FibreChannel.

NOTE: This section applies only to FC. If you are using only iSCSI with Windows, go to iSCSI HBA Configuration.

NOTE: Before you proceed, review Fibre Channel SAN Guidelines.

3

18 Host Configuration for Microsoft Windows

Pre-RequisitesThis section describes the pre-requisites for FC HBA configuration.

• Refer to the E-Lab Interoperability Navigator (https://elabnavigator.emc.com) for supported FC HBA models and drivers.• Verify all HBAs are at the supported driver, firmware and BIOS versions.• Verify all HBAs BIOS settings are configured according to E-Lab recommendations. Follow the procedures in one of the following

documents according to the FC HBA type:

○ For Qlogic HBAs, refer to the Dell EMC Host Connectivity with Qlogic FIbre Channel and iSCSI HBAs and Converged NetworkAdapters (CNAs) for the Windows Environment document.

○ For Emulex HBAs, refer to the Dell EMC Host Connectivity with Emulex Fibre Channel and iSCSI HBAs and Converged NetworkAdapters (CNAs) for the Windows Environment document.

○ For Cisco UCS fNIC HBAs, refer to the Cisco UCS Virtual Interface Card Drivers for Windows Installation Guide for completedriver installation instructions (https://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/sw/vic_drivers/install/Windows/b_Cisco_VIC_Drivers_for_Windows_Installation_Guide.html).

iSCSI ConfigurationThis section describes the recommended configuration that should be applied when attaching hosts to PowerStorecluster using iSCSI.

NOTE: This section applies only to iSCSI. If you are using only Fibre Channel with Windows and PowerStore, go to Fibre

Channel HBA Configuration. Make sure you review iSCSI SAN Guidelines before you proceed.

Pre-RequisitesThis section describes the pre-requisites when attaching hosts to PowerStore c.uster using iSCSI.

Follow the Microsoft recommendations for installation and setup of the appropriate NIC/iSCSI HBA for your system. It is recommended toinstall the latest NIC/iSCSI HBA driver version (patch), as described in the support documentation for each specific NIC/iSCSI HBA.

Refer to the E-Lab Interoperability Navigator (https://elabnavigator.emc.com) for supported NIC/iSCSI HBA models and drivers.

Multipathing Software ConfigurationThis topic introduces Multipathing Software Configuration for Microsoft Windows

PowerStore supports native multipathing using Microsoft Native Microsoft Multipath I/O (MPIO) with Windows Server 2008 and above,or multipathing using PowerPath.

Configuring Native Multipathing Using MicrosoftMultipath I/O (MPIO)This topic describes configuring native multipathing using Microsoft Multipath I/O (MPIO).

For optimal operation with PowerStore storage, configure the Round-Robin (RR) policy for MPIO for devices presented from PowerStore.Using this policy, I/O operations are balanced across all available paths.

To configure the native multipathing, using Microsoft Multipath I/O (MPIO), you should perform the following task:

Enabling MPIO on the Windows Host and Configuring MPIO for PowerStore Volumes Presented to the Host

Enabling MPIO on the Windows Host and Configuring MPIO forPowerStore Volumes Presented to the HostThis topic describes enabling and configuring MPIO on the Windows host.

About this task

Before configuring the native multipathing, you should enable MPIO on the server by adding the MPIO feature to Windows.

Host Configuration for Microsoft Windows 19


https://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/sw/vic_drivers/install/Windows/b_Cisco_VIC_Drivers_for_Windows_Installation_Guide.html

https://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/sw/vic_drivers/install/Windows/b_Cisco_VIC_Drivers_for_Windows_Installation_Guide.html


Steps

1. Open PowerShell on the host.2. Run the following commands to install MPIO if it is not already installed:

Get-WindowsOptionalFeature -Online -FeatureName MultiPathIOEnable-WindowsOPtionalFeature -Online -FeatureName MultiPathIO

3. Run the following commands to set vid/pid and RoundRobin failover policy:

New-MSDSMSupportedHW -VendorId DellEMC -ProductId PowerStoreSet-MSDSMGlobalDefaultLoadBalancePolicy -Policy RR

4. Run the following commands to set MPIO timeout values:

Set-MPIOSetting -NewPathVerificationState EnabledSet-MPIOSetting -NewPathVerificationPeriod 30Set-MPIOSetting -NewPDORemovePeriod 20Set-MPIOSetting -NewRetryCount 3Set-MPIOSetting -NewRetryInterval 3Set-MPIOSetting -custompathrecovery enabledSet-MPIOSetting -newpathrecoveryinterval 10Set-MPIOSetting -NewDiskTimeout 30

5. To verify MPIO settings on the host, run the following command:

Get-MPIOSetting

Post-Configuration Steps - Using the PowerStoreStorageThis topic describes the post-configuration steps using the PowerStore Storage.

After the host configuration is completed, you can use the PowerStore storage from the host. For details on creating, presenting andmanaging volumes accessed from the host via either the GUI or the CLI, refer to the PowerStore User Guide that matches the versionrunning on your PowerStore cluster.

Disk FormattingThis topic discusses disk formatting.

When creating volumes in PowerStore for a Windows host, the following considerations should be made:

• Disk Logical Block Size – Generally, a 512B logical block size should be used for a new PowerStore volume.

NOTE: For details on formatting a newly created volume (using either the WebUI or the GUI interfaces), refer to the

PowerStore User Guide that matches the version running on your PowerStore cluster.

Presenting PowerStore Volumes to the Windows HostThis topic discusses presenting PowerStore Volumes to the Windows host.

When adding host groups and hosts to allow Windows hosts to access PowerStore volumes, specify Windows as the operating systemfor the newly-created hosts.

NOTE: Setting the host’s operating system is required for optimal interoperability and stability of the host with

PowerStore storage. You can adjust the setting while the host is online and connected to the PowerStore cluster with

no I/O impact.

NOTE: Refer to the PowerStore User Guide that matches the version running on your PowerStore cluster.

20 Host Configuration for Microsoft Windows

Creating a File SystemThis topic discusses creating a file system.

File system configuration and management are out of the scope of this document.

NOTE: Some file systems may require you to properly-align the file system on the PowerStore volume. It is

recommended to use specified tools to optimally match your host with application requirements.

NOTE: Creating a file system formatting with UNMAP enabled on a host connected to PowerStore may result in an

increased amount of write I/Os to the storage subsystem. It is highly recommended to disable UNMAP during file

system creation.

To disable UNMAP during file system creation:

1. Open a Windows CMD window on the host.2. Run the following fsutil command to temporarily disable UNMAP on the host (prior to file system creation):

fsutil behavior set DisableDeleteNotify 13. Once file system creation is complete, re-enable UNMAP by running the following command:

fsutil behavior set DisableDeleteNotify 0NOTE: To verify the current setting of the file system, run the following fsutil command:

fsutil behavior query DisableDeleteNotify

• DisableDeleteNotify=0 - Indicates that the 'Trim and Unmap' feature is on (enabled).

• DisableDeleteNotify=1 - Indicates that the 'Trim and Unmap' feature is off (disabled).

Host Configuration for Microsoft Windows 21

Host Configuration for Linux


Topics:

• Recommended Configuration Values Summary• Fibre Channel Configuration• iSCSI Configuration• Multipathing Software Configuration• Post-Configuration Steps - Using the PowerStore Cluster

Recommended Configuration Values SummaryThe following table summarizes all used and recommended variables and their values when configuring hosts for Linux.



Validation: Specify Linux as the operatingsystem for each defined host.

Serviceability Mandatory Presenting PowerStoreVolumes to the Linux Host

Native Multipathing:

To configure the PowerStore disk device,modify /etc/multipath.conf file:

• vendor - "DellEMC"

• product - "PowerStore"

• path_selector - "queue-length 0"

• path_grouping_policy -"group_by_prio"

• path_checker - "tur"

• detect_prio - "yes"

• failback - "immediate"

• no_path_retry - "3"

• rr_min_io_rq - "1"

• fast_io_fail_tmo - "15"

• max_sectors_kb - "1024"

Performance Recommended Configuring Linux NativeMultipathing

iSCSI Configuration:

To configure the PowerStore disk device,modify /etc/iscsi/iscsid.conf file:

• Setnode.session.timeo.replacement_timeout = 15

Performance Recommended Configuring PowerStoreCluster Disk Device withiSCSI

Temporarily disable UNMAP during file systemcreation.

• When creating a file system using themke2fs command - Use the "-Enodiscard" parameter

Performance Recommended Creating a File System

4

22 Host Configuration for Linux


• When creating a file system using themkfs.xfs command - Use the "-K"parameter

Fibre Channel ConfigurationThis section describes the recommended configuration that should be applied when attaching hosts to PowerStore cluster using FibreChannel.

NOTE: This section applies only to FC. If you are using only iSCSI with Linux, go to iSCSI HBA Configuration.

NOTE: Before proceeding, review Fibre Channel SAN Guidelines.

Pre-RequisitesWhen attaching a host to PowerStore cluster using Fibre Channel, the following pre-requisites need to be met:

• Refer to the E-Lab Interoperability Navigator (https://elabnavigator.emc.com) for supported Fibre Channel HBA models and drivers.• Verify all HBAs are at the supported driver, firmware and BIOS versions.• Verify all HBAs BIOS settings are configured according to E-Lab recommendations.

iSCSI ConfigurationThis section provides an introduction to the recommended configuration to be applied when attaching hosts to PowerStore cluster usingiSCSI.

NOTE: This section applies only to iSCSI. If you are using only Fibre Channel with Linux and PowerStore, go to Fibre

Channel Configuration.

NOTE: Before proceeding, review the iSCSI SAN Guidelines section.

Pre-RequisitesRefer to the E-Lab Interoperability Navigator (https://elabnavigator.emc.com) for supported NIC/iSCSI HBA models and drivers.

Configuring the PowerStore Cluster Disk Device withiSCSITo configure the PowerStore disk device, modify the configuration file with the following parameters.

The configuration file for the multipath daemon is multipath.conf. It is used to overwrite the built-in configuration table of the multipathdaemon. When iSCSI is used with PowerStore, the iscsi.conf file is used to overwrite iSCSI specific multipathing related settings.

To configure the PowerStore disk device, modify the /etc/iscsi/iscsid.conf file, using the following parameters:

NOTE: The example below is based on RedHat. For details on configuring PowerStore disk device with iSCSI, refer to

the specific instructions of your operating system.

Parameter Description Value

node.session.timeo.replacement_timeout Specifies the number of seconds the iSCSI layer waits for a timed-out path/session to re-establish before failing any commands on thatpath/session. The default value is 120.

15

Using these settings prevents commands from being split by the iSCSI initiator and enables instantaneous mapping from the host to thevolume.

To apply the adjusted iscsid.conf settings, run the following command on the Linux host:

Host Configuration for Linux 23



service iscsi restartNOTE: If a previous iSCSI target is discovered on the Linux host, delete the iSCSI DB and rerun the iSCSI target

discovery procedure with the iscsid.conf setting described above.

Configuring the PowerStore Cluster Disk Device withiSCSI - Single Network Subnet SupportThis topic describes the issue of single subnet support for iSCSI target portals.

In PowerStore, only single network subnet is supported for the iSCSI target portals.

By design, on various Linux distributions, only two network interfaces can be configured on the same network subnet. For details, refer toRedHat KB 30564 (https://access.redhat.com/solutions/30564) and RedHat KB 53031 (https://access.redhat.com/solutions/53031).

In light of this limitation, use one of the following solutions to make both network interfaces accessible with hosts connected toPowerStore storage:

• Policy-Based Routing (recommended)• Bonding/Teaming• Disable Reverse Path Filtering

Policy-Based RoutingThis topic outlines policy-based routing as a solution to the single network subnet limitation (recommended solution).

This solution is based on adding routing tables and rules, binding source IP address for each route, and adding those as default gatewaysfor each network interface.

Using this solution, a routing table is defined for each interface, thus the default routing table is redundant for those interfaces.

For additional technical information on Policy-Based Routing, refer to https://access.redhat.com/solutions/30564.

Bonding/TeamingThis topic outlines bonding/teaming as a solution to the single network subnet limitation.

NOTE: The following section does not apply to hosts directly attached to the PowerStore appliances.

This solution is based on the Bond and Network teaming configuration.

• Bond - Binding multiple network interfaces into a single bonded channel enables them to act as one virtual interface. That way, only asingle network address is defined and the said limitation does not apply.

For additional technical information on configuring network bond on Red Hat Enterprise Linux 7, refer to https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/ch-configure_network_bonding.

• Network Teaming - With Red Hat Enterprise Linux 7, Network Teaming is offered as a new implementation of the bonding concept.The existing bonding driver is unaffected.

Network Teaming is offered as an alternative and does not replace bonding in Red Hat Enterprise Linux 7. For additional technicalinformation on configuring Network Teaming, refer to https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/ch-configure_network_teaming.

For a comparison between Bonding and Network Teaming implementations, refer to https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/sec-comparison_of_network_teaming_to_bonding.

Disabling Reverse Path FilteringThis topic outlines disabling reverse path filtering as a solution to the single network subnet limitation.

RHEL 6 and above are configured by default to apply Strict Reverse Path Forwarding filtering recommended in RFC 3704 - IngressFiltering for Multihomed Networks.

NOTE: Before making this change, refer to the Root Cause section of this article to understand what it does and review

alternative solutions as explained in https://access.redhat.com/solutions/53031.

Setting the Reverse Path Filtering to 2 (loose) on the relevant network interfaces makes them both accessible and routable.

To apply this change, add the following lines to /etc/sysctl.conf:


https://access.redhat.com/solutions/30564



https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/ch-configure_network_bonding

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/ch-configure_network_bonding

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/ch-configure_network_teaming

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/ch-configure_network_teaming

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/sec-comparison_of_network_teaming_to_bonding

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/sec-comparison_of_network_teaming_to_bonding


net.ipv4.conf.eth2.rp_filter = 2net.ipv4.conf.eth3.rp_filter = 2

NOTE: In this example, eth2 and eth3 are the network interfaces used for iSCSI. Make sure to modify to the relevant

interfaces.

To reload the configuration:

sysctl -pTo view the current Reverse Path Filtering configuration on the system:

sysctl -ar "\.rp_filter"

net.ipv4.conf.all.rp_filter = 1net.ipv4.conf.default.rp_filter = 1net.ipv4.conf.eth0.rp_filter = 1net.ipv4.conf.eth1.rp_filter = 1net.ipv4.conf.eth2.rp_filter = 2net.ipv4.conf.eth3.rp_filter = 2net.ipv4.conf.lo.rp_filter = 0

Multipathing Software Configuration

Configuring Linux Native MultipathingFor a PowerStore cluster to function properly with Linux hosts, configure the multipath settings file /etc/multipath.conf:

NOTE: If the host is connected to a cluster other than PowerStore, the configuration file may include additional devices.

NOTE: If the multipath.conf file includes a blacklist section, it should come before the devices section. For additional

information, refer to the Importing External Storage to PowerStore Guide document.

devices {device{vendor DellEMCproduct PowerStorepath_selector "queue-length 0"path_grouping_policy group_by_priopath_checker turdetect_prio yesfailback immediateno_path_retry 3rr_min_io_rq 1fast_io_fail_tmo 15max_sectors_kb 1024 //only for RHEL 6.9 (or later 6.x versions) and RHEL 7.4 (or later 7.xversions)}//other devices}}


vendor Specifies the vendor name DellEMC

product The below configuration applies only to PowerStore volumes. PowerStore



path_selector Sends the next group of I/Os to the path with the least number ofoutstanding I/O requests

queue-length 0

path_grouping_policy Specifies the default path grouping policy to apply to PowerStorevolumes

• Paths are grouped by priorities assigned by the cluster.• A higher priority (50) is set as Active/Optimized. Lower priority

(10) is set as Active/Non-Optimized.

group_by_prio

path_checker Specifies TEST UNIT READY as the default method used to determinethe state of the paths.

tur

detect_prio If set to yes, multipath will try to detect whether the device supportsALUA. If so, the device will automatically use the alua prioritizer.Otherwise, the prioritizer will be selected as usual. Default value is no.

yes

failback Manages the path group failback. Immediate refers to immediatefailback to the highest priority path group that contains active paths.

Immediate

no_path_retry Specifies the number of times the system should attempt to use afailed path before disabling queuing.

3

rr_min_io_rq Specifies the number of I/O requests to route to a path beforeswitching to the next path in the same path group, using request-based device-mapper-multipath. This setting should be used onsystems running current kernels. On systems running kernels older than2.6.31, use rr_min_io. Default value is 1.

1

fast_io_fail_tmo Specifies the number of seconds the scsi layer will wait after a problemhas been detected on a FC remote port before failing I/O to devices onthat remote port. This value should be smaller than dev_loss_tmo.Setting this parameter to off will disable the timeout.

15

max_sectors_kb Applies to Red Hat Enterprise Linux Release 6.9 (or later 6.x versions)and Red Hat Enterprise Linux Release 7.4 (or later 7.x versions).

Sets the max_sectors_kb device queue parameter to the specifiedvalue on all underlying paths of a multipath device before the multipathdevice is first activated. When a multipath device is created, the deviceinherits the max_sectors_kb value from the path devices. Manuallyraising this value for the multipath device or lowering it for the pathdevices can cause multipath to create I/O operations larger than thepath devices allow. Using the max_sectors_kb parameter is an easyway to set these values before a multipath device is created on top ofthe path devices and prevent invalid-sized I/O operations from beingpassed. If this parameter is not set by the user, the path devices haveit set by their device driver, and the multipath device inherits it fromthe path devices.

NOTE: In PowerStore cluster the maximum I/O size is 1MB.PowerStore does not set an optimal transfer size.

1024

Post-Configuration Steps - Using the PowerStoreClusterAfter the host configuration is completed, you can access the PowerStore cluster from the host.

For details on creating, presenting and managing volumes accessed from the host via either the GUI or the CLI, refer to the PowerStoreUser Guide that matches the version running on your PowerStore cluster.


Presenting PowerStore Cluster Volumes to the Linux HostThis topic provides guidelines for presenting PowerStore cluster volumes to the Linux host.

• When adding host groups and hosts to allow Linux hosts to access PowerStore cluster volumes, specify Linux as the operatingsystem for the newly created hosts.

• Setting the operating system of the host is required for optimal interoperability and stability of the host with PowerStore clusterstorage. You can adjust the setting while the host is online and connected to the PowerStore cluster with no I/O impact.

NOTE: Refer to the PowerStore User Guide that matches the version running on your PowerStore cluster for details.

Partition Alignment in LinuxUse the fdisk command to create partition alignment on a PowerStore cluster volume.

To align partitions on PowerStore cluster volumes that are presented to Linux hosts, use the default value (2048). Then, create a partitionusing the fdisk command to ensure that the file system is aligned.

When you perform partition alignment, the logical device (/dev/mapper/<naa-name>) should be used rather than the physical device(/dev/<device>). When multipathing is not used (for example in a virtual machine), the physical device should be used.

The following example demonstrates using the fdisk command to create an aligned partition on a PowerStore cluster volume.

[root@lg114 ~]# fdisk -cu /dev/mapper/ 368ccf098003f1461569ea4750e9dac50Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabelBuilding a new DOS disklabel with disk identifier 0x12d4e90c Changes will remain in memeory only, until you decide to write them. After that, of course, the previouscontent won't be recoverable.Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

Command (m for help): p

Disk /dev/mapper/3514f0c5b12a00004: 1649.3 GB, 1649267441664 bytes255 heads, 63 sectors/track, 200512 cylinders, total 3221225472 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytes I/O size(minimum/optimal): 16384 bytes / 65536 bytes Disk identifier: 0x12d4e90c Device Boot Start End Blocks Id System

In this mode, rather than using "cylinders" for creating partitions, the fdisk command uses sectors, which are a direct mapping to theLBA space of the cluster. Thus, to verify that the partition is aligned, simply verify that the starting sector number is a multiple of 16 (16sectors, at 512 bytes each, is 8 KB). The fdisk command defaults to a starting sector for the first partition of 2048, which is divisible by16, and thus is correctly assigned.

Creating a File SystemFor creating a file system with PowerStore cluster storage, follow these guidelines:

It is recommended to create the file system using its default block size (using a non-default block size may lead to unexpected behavior).Refer to your operating system and file system documentation.

NOTE: Creating a file system with UNMAP enabled on a host connected to PowerStore may result in an increased

amount of write I/Os to the storage subsystem. It is highly recommended to disable UNMAP during file system creation.

To disable UNMAP during file system creation:

• When creating a file system using the mke2fs command - Use the "-E nodiscard" parameter.

• When creating a file system using the mkfs.xfs command - Use the "-K" parameter.

For a more efficient data utilization and better performance, use Ext4 file system with PowerStore cluster storage instead of Ext3. Fordetails on converting to Ext4 file system (from either Ext3 or Ext2), refer to https://ext4.wiki.kernel.org/index.php/UpgradeToExt4.

NOTE: File system configuration and management are out of the scope of this document.


https://ext4.wiki.kernel.org/index.php/UpgradeToExt4

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